tools/perf/util/bpf-event.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <stdlib.h>
   4 #include <bpf/bpf.h>
   5 #include <bpf/btf.h>
   6 #include <bpf/libbpf.h>
   7 #include <linux/btf.h>
   8 #include <linux/err.h>
   9 #include <linux/string.h>
  10 #include <internal/lib.h>
  11 #include <symbol/kallsyms.h>
  12 #include "bpf-event.h"
  13 #include "debug.h"
  14 #include "dso.h"
  15 #include "symbol.h"
  16 #include "machine.h"
  17 #include "env.h"
  18 #include "session.h"
  19 #include "map.h"
  20 #include "evlist.h"
  21 #include "record.h"
  22 #include "util/synthetic-events.h"
  23
  24 #define ptr_to_u64(ptr)    ((__u64)(unsigned long)(ptr))
  25
  26 static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)
  27 {
  28         int ret = 0;
  29         size_t i;
  30
  31         for (i = 0; i < len; i++)
  32                 ret += snprintf(buf + ret, size - ret, "%02x", data[i]);
  33         return ret;
  34 }
  35
  36 static int machine__process_bpf_event_load(struct machine *machine,
  37                                            union perf_event *event,
  38                                            struct perf_sample *sample __maybe_unused)
  39 {
  40         struct bpf_prog_info_linear *info_linear;
  41         struct bpf_prog_info_node *info_node;
  42         struct perf_env *env = machine->env;
  43         int id = event->bpf.id;
  44         unsigned int i;
  45
  46         /* perf-record, no need to handle bpf-event */
  47         if (env == NULL)
  48                 return 0;
  49
  50         info_node = perf_env__find_bpf_prog_info(env, id);
  51         if (!info_node)
  52                 return 0;
  53         info_linear = info_node->info_linear;
  54
  55         for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
  56                 u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);
  57                 u64 addr = addrs[i];
  58                 struct map *map = maps__find(&machine->kmaps, addr);
  59
  60                 if (map) {
  61                         map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
  62                         map->dso->bpf_prog.id = id;
  63                         map->dso->bpf_prog.sub_id = i;
  64                         map->dso->bpf_prog.env = env;
  65                 }
  66         }
  67         return 0;
  68 }
  69
  70 int machine__process_bpf(struct machine *machine, union perf_event *event,
  71                          struct perf_sample *sample)
  72 {
  73         if (dump_trace)
  74                 perf_event__fprintf_bpf(event, stdout);
  75
  76         switch (event->bpf.type) {
  77         case PERF_BPF_EVENT_PROG_LOAD:
  78                 return machine__process_bpf_event_load(machine, event, sample);
  79
  80         case PERF_BPF_EVENT_PROG_UNLOAD:
  81                 /*
  82                  * Do not free bpf_prog_info and btf of the program here,
  83                  * as annotation still need them. They will be freed at
  84                  * the end of the session.
  85                  */
  86                 break;
  87         default:
  88                 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
  89                 break;
  90         }
  91         return 0;
  92 }
  93
  94 static int perf_env__fetch_btf(struct perf_env *env,
  95                                u32 btf_id,
  96                                struct btf *btf)
  97 {
  98         struct btf_node *node;
  99         u32 data_size;
 100         const void *data;
 101
 102         data = btf__get_raw_data(btf, &data_size);
 103
 104         node = malloc(data_size + sizeof(struct btf_node));
 105         if (!node)
 106                 return -1;
 107
 108         node->id = btf_id;
 109         node->data_size = data_size;
 110         memcpy(node->data, data, data_size);
 111
 112         if (!perf_env__insert_btf(env, node)) {
 113                 /* Insertion failed because of a duplicate. */
 114                 free(node);
 115                 return -1;
 116         }
 117         return 0;
 118 }
 119
 120 static int synthesize_bpf_prog_name(char *buf, int size,
 121                                     struct bpf_prog_info *info,
 122                                     struct btf *btf,
 123                                     u32 sub_id)
 124 {
 125         u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
 126         void *func_infos = (void *)(uintptr_t)(info->func_info);
 127         u32 sub_prog_cnt = info->nr_jited_ksyms;
 128         const struct bpf_func_info *finfo;
 129         const char *short_name = NULL;
 130         const struct btf_type *t;
 131         int name_len;
 132
 133         name_len = snprintf(buf, size, "bpf_prog_");
 134         name_len += snprintf_hex(buf + name_len, size - name_len,
 135                                  prog_tags[sub_id], BPF_TAG_SIZE);
 136         if (btf) {
 137                 finfo = func_infos + sub_id * info->func_info_rec_size;
 138                 t = btf__type_by_id(btf, finfo->type_id);
 139                 short_name = btf__name_by_offset(btf, t->name_off);
 140         } else if (sub_id == 0 && sub_prog_cnt == 1) {
 141                 /* no subprog */
 142                 if (info->name[0])
 143                         short_name = info->name;
 144         } else
 145                 short_name = "F";
 146         if (short_name)
 147                 name_len += snprintf(buf + name_len, size - name_len,
 148                                      "_%s", short_name);
 149         return name_len;
 150 }
 151
 152 /*
 153  * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
 154  * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
 155  * one PERF_RECORD_KSYMBOL is generated for each sub program.
 156  *
 157  * Returns:
 158  *    0 for success;
 159  *   -1 for failures;
 160  *   -2 for lack of kernel support.
 161  */
 162 static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
 163                                                perf_event__handler_t process,
 164                                                struct machine *machine,
 165                                                int fd,
 166                                                union perf_event *event,
 167                                                struct record_opts *opts)
 168 {
 169         struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
 170         struct perf_record_bpf_event *bpf_event = &event->bpf;
 171         struct bpf_prog_info_linear *info_linear;
 172         struct perf_tool *tool = session->tool;
 173         struct bpf_prog_info_node *info_node;
 174         struct bpf_prog_info *info;
 175         struct btf *btf = NULL;
 176         struct perf_env *env;
 177         u32 sub_prog_cnt, i;
 178         int err = 0;
 179         u64 arrays;
 180
 181         /*
 182          * for perf-record and perf-report use header.env;
 183          * otherwise, use global perf_env.
 184          */
 185         env = session->data ? &session->header.env : &perf_env;
 186
 187         arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
 188         arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
 189         arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
 190         arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
 191         arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
 192         arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
 193         arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
 194
 195         info_linear = bpf_program__get_prog_info_linear(fd, arrays);
 196         if (IS_ERR_OR_NULL(info_linear)) {
 197                 info_linear = NULL;
 198                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 199                 return -1;
 200         }
 201
 202         if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
 203                 pr_debug("%s: the kernel is too old, aborting\n", __func__);
 204                 return -2;
 205         }
 206
 207         info = &info_linear->info;
 208
 209         /* number of ksyms, func_lengths, and tags should match */
 210         sub_prog_cnt = info->nr_jited_ksyms;
 211         if (sub_prog_cnt != info->nr_prog_tags ||
 212             sub_prog_cnt != info->nr_jited_func_lens)
 213                 return -1;
 214
 215         /* check BTF func info support */
 216         if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
 217                 /* btf func info number should be same as sub_prog_cnt */
 218                 if (sub_prog_cnt != info->nr_func_info) {
 219                         pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
 220                         err = -1;
 221                         goto out;
 222                 }
 223                 if (btf__get_from_id(info->btf_id, &btf)) {
 224                         pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
 225                         err = -1;
 226                         btf = NULL;
 227                         goto out;
 228                 }
 229                 perf_env__fetch_btf(env, info->btf_id, btf);
 230         }
 231
 232         /* Synthesize PERF_RECORD_KSYMBOL */
 233         for (i = 0; i < sub_prog_cnt; i++) {
 234                 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 235                 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 236                 int name_len;
 237
 238                 *ksymbol_event = (struct perf_record_ksymbol) {
 239                         .header = {
 240                                 .type = PERF_RECORD_KSYMBOL,
 241                                 .size = offsetof(struct perf_record_ksymbol, name),
 242                         },
 243                         .addr = prog_addrs[i],
 244                         .len = prog_lens[i],
 245                         .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 246                         .flags = 0,
 247                 };
 248
 249                 name_len = synthesize_bpf_prog_name(ksymbol_event->name,
 250                                                     KSYM_NAME_LEN, info, btf, i);
 251                 ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
 252                                                          sizeof(u64));
 253
 254                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 255                 event->header.size += machine->id_hdr_size;
 256                 err = perf_tool__process_synth_event(tool, event,
 257                                                      machine, process);
 258         }
 259
 260         if (!opts->no_bpf_event) {
 261                 /* Synthesize PERF_RECORD_BPF_EVENT */
 262                 *bpf_event = (struct perf_record_bpf_event) {
 263                         .header = {
 264                                 .type = PERF_RECORD_BPF_EVENT,
 265                                 .size = sizeof(struct perf_record_bpf_event),
 266                         },
 267                         .type = PERF_BPF_EVENT_PROG_LOAD,
 268                         .flags = 0,
 269                         .id = info->id,
 270                 };
 271                 memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
 272                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 273                 event->header.size += machine->id_hdr_size;
 274
 275                 /* save bpf_prog_info to env */
 276                 info_node = malloc(sizeof(struct bpf_prog_info_node));
 277                 if (!info_node) {
 278                         err = -1;
 279                         goto out;
 280                 }
 281
 282                 info_node->info_linear = info_linear;
 283                 perf_env__insert_bpf_prog_info(env, info_node);
 284                 info_linear = NULL;
 285
 286                 /*
 287                  * process after saving bpf_prog_info to env, so that
 288                  * required information is ready for look up
 289                  */
 290                 err = perf_tool__process_synth_event(tool, event,
 291                                                      machine, process);
 292         }
 293
 294 out:
 295         free(info_linear);
 296         free(btf);
 297         return err ? -1 : 0;
 298 }
 299
 300 struct kallsyms_parse {
 301         union perf_event        *event;
 302         perf_event__handler_t    process;
 303         struct machine          *machine;
 304         struct perf_tool        *tool;
 305 };
 306
 307 static int
 308 process_bpf_image(char *name, u64 addr, struct kallsyms_parse *data)
 309 {
 310         struct machine *machine = data->machine;
 311         union perf_event *event = data->event;
 312         struct perf_record_ksymbol *ksymbol;
 313         int len;
 314
 315         ksymbol = &event->ksymbol;
 316
 317         *ksymbol = (struct perf_record_ksymbol) {
 318                 .header = {
 319                         .type = PERF_RECORD_KSYMBOL,
 320                         .size = offsetof(struct perf_record_ksymbol, name),
 321                 },
 322                 .addr      = addr,
 323                 .len       = page_size,
 324                 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 325                 .flags     = 0,
 326         };
 327
 328         len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);
 329         ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));
 330         memset((void *) event + event->header.size, 0, machine->id_hdr_size);
 331         event->header.size += machine->id_hdr_size;
 332
 333         return perf_tool__process_synth_event(data->tool, event, machine,
 334                                               data->process);
 335 }
 336
 337 static int
 338 kallsyms_process_symbol(void *data, const char *_name,
 339                         char type __maybe_unused, u64 start)
 340 {
 341         char disp[KSYM_NAME_LEN];
 342         char *module, *name;
 343         unsigned long id;
 344         int err = 0;
 345
 346         module = strchr(_name, '\t');
 347         if (!module)
 348                 return 0;
 349
 350         /* We are going after [bpf] module ... */
 351         if (strcmp(module + 1, "[bpf]"))
 352                 return 0;
 353
 354         name = memdup(_name, (module - _name) + 1);
 355         if (!name)
 356                 return -ENOMEM;
 357
 358         name[module - _name] = 0;
 359
 360         /* .. and only for trampolines and dispatchers */
 361         if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) ||
 362             (sscanf(name, "bpf_dispatcher_%s", disp) == 1))
 363                 err = process_bpf_image(name, start, data);
 364
 365         free(name);
 366         return err;
 367 }
 368
 369 int perf_event__synthesize_bpf_events(struct perf_session *session,
 370                                       perf_event__handler_t process,
 371                                       struct machine *machine,
 372                                       struct record_opts *opts)
 373 {
 374         const char *kallsyms_filename = "/proc/kallsyms";
 375         struct kallsyms_parse arg;
 376         union perf_event *event;
 377         __u32 id = 0;
 378         int err;
 379         int fd;
 380
 381         event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
 382         if (!event)
 383                 return -1;
 384
 385         /* Synthesize all the bpf programs in system. */
 386         while (true) {
 387                 err = bpf_prog_get_next_id(id, &id);
 388                 if (err) {
 389                         if (errno == ENOENT) {
 390                                 err = 0;
 391                                 break;
 392                         }
 393                         pr_debug("%s: can't get next program: %s%s\n",
 394                                  __func__, strerror(errno),
 395                                  errno == EINVAL ? " -- kernel too old?" : "");
 396                         /* don't report error on old kernel or EPERM  */
 397                         err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
 398                         break;
 399                 }
 400                 fd = bpf_prog_get_fd_by_id(id);
 401                 if (fd < 0) {
 402                         pr_debug("%s: failed to get fd for prog_id %u\n",
 403                                  __func__, id);
 404                         continue;
 405                 }
 406
 407                 err = perf_event__synthesize_one_bpf_prog(session, process,
 408                                                           machine, fd,
 409                                                           event, opts);
 410                 close(fd);
 411                 if (err) {
 412                         /* do not return error for old kernel */
 413                         if (err == -2)
 414                                 err = 0;
 415                         break;
 416                 }
 417         }
 418
 419         /* Synthesize all the bpf images - trampolines/dispatchers. */
 420         if (symbol_conf.kallsyms_name != NULL)
 421                 kallsyms_filename = symbol_conf.kallsyms_name;
 422
 423         arg = (struct kallsyms_parse) {
 424                 .event   = event,
 425                 .process = process,
 426                 .machine = machine,
 427                 .tool    = session->tool,
 428         };
 429
 430         if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {
 431                 pr_err("%s: failed to synthesize bpf images: %s\n",
 432                        __func__, strerror(errno));
 433         }
 434
 435         free(event);
 436         return err;
 437 }
 438
 439 static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 440 {
 441         struct bpf_prog_info_linear *info_linear;
 442         struct bpf_prog_info_node *info_node;
 443         struct btf *btf = NULL;
 444         u64 arrays;
 445         u32 btf_id;
 446         int fd;
 447
 448         fd = bpf_prog_get_fd_by_id(id);
 449         if (fd < 0)
 450                 return;
 451
 452         arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
 453         arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
 454         arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
 455         arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
 456         arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
 457         arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
 458         arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
 459
 460         info_linear = bpf_program__get_prog_info_linear(fd, arrays);
 461         if (IS_ERR_OR_NULL(info_linear)) {
 462                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 463                 goto out;
 464         }
 465
 466         btf_id = info_linear->info.btf_id;
 467
 468         info_node = malloc(sizeof(struct bpf_prog_info_node));
 469         if (info_node) {
 470                 info_node->info_linear = info_linear;
 471                 perf_env__insert_bpf_prog_info(env, info_node);
 472         } else
 473                 free(info_linear);
 474
 475         if (btf_id == 0)
 476                 goto out;
 477
 478         if (btf__get_from_id(btf_id, &btf)) {
 479                 pr_debug("%s: failed to get BTF of id %u, aborting\n",
 480                          __func__, btf_id);
 481                 goto out;
 482         }
 483         perf_env__fetch_btf(env, btf_id, btf);
 484
 485 out:
 486         free(btf);
 487         close(fd);
 488 }
 489
 490 static int bpf_event__sb_cb(union perf_event *event, void *data)
 491 {
 492         struct perf_env *env = data;
 493
 494         if (event->header.type != PERF_RECORD_BPF_EVENT)
 495                 return -1;
 496
 497         switch (event->bpf.type) {
 498         case PERF_BPF_EVENT_PROG_LOAD:
 499                 perf_env__add_bpf_info(env, event->bpf.id);
 500
 501         case PERF_BPF_EVENT_PROG_UNLOAD:
 502                 /*
 503                  * Do not free bpf_prog_info and btf of the program here,
 504                  * as annotation still need them. They will be freed at
 505                  * the end of the session.
 506                  */
 507                 break;
 508         default:
 509                 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
 510                 break;
 511         }
 512
 513         return 0;
 514 }
 515
 516 int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
 517 {
 518         struct perf_event_attr attr = {
 519                 .type             = PERF_TYPE_SOFTWARE,
 520                 .config           = PERF_COUNT_SW_DUMMY,
 521                 .sample_id_all    = 1,
 522                 .watermark        = 1,
 523                 .bpf_event        = 1,
 524                 .size      = sizeof(attr), /* to capture ABI version */
 525         };
 526
 527         /*
 528          * Older gcc versions don't support designated initializers, like above,
 529          * for unnamed union members, such as the following:
 530          */
 531         attr.wakeup_watermark = 1;
 532
 533         return perf_evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
 534 }
 535
 536 void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
 537                                       struct perf_env *env,
 538                                       FILE *fp)
 539 {
 540         __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 541         __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 542         char name[KSYM_NAME_LEN];
 543         struct btf *btf = NULL;
 544         u32 sub_prog_cnt, i;
 545
 546         sub_prog_cnt = info->nr_jited_ksyms;
 547         if (sub_prog_cnt != info->nr_prog_tags ||
 548             sub_prog_cnt != info->nr_jited_func_lens)
 549                 return;
 550
 551         if (info->btf_id) {
 552                 struct btf_node *node;
 553
 554                 node = __perf_env__find_btf(env, info->btf_id);
 555                 if (node)
 556                         btf = btf__new((__u8 *)(node->data),
 557                                        node->data_size);
 558         }
 559
 560         if (sub_prog_cnt == 1) {
 561                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
 562                 fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
 563                         info->id, name, prog_addrs[0], prog_lens[0]);
 564                 goto out;
 565         }
 566
 567         fprintf(fp, "# bpf_prog_info %u:\n", info->id);
 568         for (i = 0; i < sub_prog_cnt; i++) {
 569                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);
 570
 571                 fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
 572                         i, name, prog_addrs[i], prog_lens[i]);
 573         }
 574 out:
 575         btf__free(btf);
 576 }